ive tried search, includeing google

87 XJ 4.0

my oil light has been staying on after startup,for about 3-4 seconds give or take

it has a wix filter, just getting that out of the way.

is this normal or do you think my sending unit is on its way out

 

Could be the sending unit, or it could indicate an internal engine problem.

Either get a "mechanical" oil pressure gauge on there (installed where your oil pressure sending unit resides) or roll the dice and buy a new sending unit. If you do that, buy it from Jeep for the best reliability/accuracy/mating with your factory gauge.

BTW, my strategy for any low oil pressure situation is to verify with a mechanical gauge. Then you know for SURE. Many big box parts stores will rent you a mechanic gauge inexpensively. Call around.

 

I don't hear any excess engine noise. I hope it's not internal. I might just replace the sending unit and see if it helps.

On a side note it didn't do this before. I did an oil change and got rid of my fram filter. Put on a wix using 10 30 oil and now it does this.

 

Anybody else have any ideas

 

Yes. Same as above. Don't do anything til you verify true oil pressure.

 

on another note, the OEM oil sending unit is no longer available from the dealer for my XJ

 

Just verify with a mechanical gauge, and if you need a new sender just go aftermarket.

 

remove old one see if there crap in it

 

i went out and bought a testing kit, im going to wait till tomorrow to test cause it seems to happen more on cold rather then hot.

what type of numbers should i be looking for? and if its low only for about 3 seconds after startup what could that be.

fyi it has a new oil pump i just installed about 3 months ago, a wix oil filter a few weeks ago, it is leaking oil, i just did the pan gasket and the rear main so im thinking valve gasket or adapter o ring

 

Ever read this thread?

http://www.jeepforum.com/forum/f19/4...fixed-1304679/

 

yes i have thank you
when i pull off the sender to test my pressure i plan on checking it out and cleaning out any sludge

 

You might want to consider changing over to 5W-30 synthetic.

 

I've heard of people using 15 40. But not that before.

Would synthetic be ok in an 87 with almost 220k on the engine.

 

Sure. I run it in mine.

 

i know this is an old thread but i finally got around to putting a oil pressure tester on.

keep in mind its an 87 xj 4.0

i have two diffrent gauges the first one is 0-50psi

upon cold startup the gauge slowly builds pressure for about 3 seconds then BAM pegs out at 50psi....i rev it a little and no change.

i take off that gauge and put one on that measures in incraments of 100

start her up and shes sitting right around the 60psi mark, rev her a little and it barley changes

whats going on here, that seems a little high to me and the slow buildup of pressure worrys me.

what could cause high pressure, and what could cause the slow build up

fyi im using 10 30 oil and a wix filter